Tractor of the endless-track type.



w. 0. STARK.

TRACTOR OF THE ENDLESS TRACK TYPE.

APPLICATION FILED AUG-20, 1913.

1,204,516. Patented Nov. 14,1916.

3 SHEETS-SHEET I.

W. O. STARK.

TRACTOR OF THE ENDLESS TRACK TYPE.

APPLICATION FILED AUG-20, 1913. 4

1 304,5 1 6. Patented Nov. 14, 1916.-

3 SHEETSSHEET 2.

Tisha w. 0. STARK. TRACTOR OF THE ENDLESS TRACK TYPE.

APPLICATION FILED AUG-20. I913.

Pafented Nov. 14, 1916.

3 SHEETS-SHEET 3.

&

'WJ as s UNITED STATES PATENT OFFICE.

WILLIAM O. STARK, OF CHICAGO, ILLIN' OIS, ASSIGNOR TO BULLOCK TRACTOR COMPANY, OF CmCAGO, ILLINOIS, A CORPORATION.

TRACTOR OF THE ENDLESS-TRACK TY PE.

Specification of Letters Patent.

Patented Nov. 14, 1916.

Application filed August 20, 1913. Serial No. 785,675.

T 0 all whom it may concern g Be it known that I, WILLIAMYO. STARK, a citizen of the United States, and resident of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Tractors of the Endless-Track Type; and I do hereby declare that the following description of my said invention, taken in connection with the accompanying sheets of drawings, form a full, clear, and exact specification, which will enable others skilled in the art to which my' said invention appertains to make and use the same.

This invention has general reference to tractors of the endless track type; and it consists, essentially, in the novel and peculiar combination of parts, and details of construction, as hereinafter first fully set forth and described, and thenpointed out in the claims.

In the drawings already mentioned, which serve to illustrate this invention inore fully and form a part of this specification, Figure 1 is a side-elevation of a tractor embodying my said invention. Fig. 2 is a plan of the chassis of this machine. Fig. 3 is a sectional view on line 33 of Fig. 2. Fig. 4 is a similar view on line 44 of Fig. 2. Fig. 5 is a side-elevation of one of the trucks detached, and Fig. 6 is a plan of the same. I

Like parts are designated by the same characters and symbols of reference in all the figures.

V The object of this invention is the produc- I tion of an efiicient,'serviceable and durable traction engine in which endless tracks are employed for both propelling and steering the machine.

In the drawings A designates the chassis or subframe of this machine. It includes longitudinal side sills 12, 13, preferably formed of channel bars, end I-beams 14, 15,.

four longitudinal I-beams 16, 17, 18, and 19, connecting the end I-beams 14, 15, two transverse channels 20, 21, connected to the longitudinal I-beams 17, 18, and two longitudinal channels 22, 23, located upon and connect:

ing the channels 20, 21. In the rear of the transverse channel, 21, there are located two transverse I-beams 24, 25; also connecting the two longitudinal I-beams 17, 18, and

upon these beams there is placed an open bed-plate 26, upon which is mounted the friction drive constructed substantially like closure of this said invention.

Upon the longitudinal channels 22, 23,-

there is mounted a motor, B, preferably of the internal combustion type, the engine shaft 27, of which actuates thedriving mechanism, as will hereinafter more fully appear.

Near the forward ends of the silk 12, 13, there are pendant plates 28, 28, 29, 29', the lower ends of which aflord guides for truck fi aines, hereinafter described, in conjunction with further pendant plates 30, 30", 31, 31*, at the rear end of the chassis A, all of said plates having braces 32 to afford stiffeners for said plates to prevent lateral movement The propelling or traction mechanism proper includes two endless track bands C, mounted in truck frames occupying the spaces 33. 34, Fig. 2, formed by the longitudinal sills and I-beams 12, 16, 19, and 13 of the chassis, one of said truck frames and itsvappurtenants being shown in detail in Figs. 5 and 6, and comprises two side-bars 35, 35 in parallel spaced relation, said sidebars having at their rear ends bearings, 36, 36, for the reception of a shaft 37, upon which shaft there is mounted a two-part sprocket-wheel 38, which constitutes the driver for an endless track band C of any suitable construction, the one shown being of a special design which forms the subject matter of an application for Letters Patent filed August 20, 1913, Serial No. 785,672 concurrent with this present one. This endless track-band comprises a series of transverse plates or shoes 72, formed each with a box-shaped link section 73, the upper surface 74 of which constitutes the track on which the vehicle moves. These box-shaped link sections are hingedly connected bypins or bolts 75. From the side-walls of the linksections 7 3 project laterally, cylindrical bosses, 76, which bosses form, as it were, racks which are engaged by the cogs or teeth 77 of the twin driver sprocket 38, and thereby cause. the forward, or rearward movement, as the case may be, of the machine. It will thus be seen that inasmuch as the bosses 76 project from both sides of the box-shaped link sections 73' and are engaged by the twin driving sprockets, the movement of the machine on its endless-track is greatly facilitated.

The twin sprocket 3 is preferably formed in two parts each of which has one of said sprockets, and one-half of a drum, 78, which drum runs on the track-surface 74, of the link sections 7 3 and which drum carries its portion of the superposed weight of the machine, said drum and the bearing or track surface 74 being made rather wide for obvious reasons, there being no weight or load Whatever imposed upon the sprocketportion of said twin driving sprocket. And for the same reason, the bearing rollers 45, and supporting or guiding rollers 48, are made with correspondingly wide faces.

The cogs or teeth 77 of the sprocket wheels are outwardly flared, as shown at 7 5) in Fig. 6, and terminate in nearly sharp edges which in rotation of the sprockets, function as knives to cut away any solid matter that may adhere to the link-sections.

I have shown in the drawings the driving twin sprocket wheel provided with only four sprocket-teeth each, but it is evident that any other larger number of sprocketteeth may be employed if desired or found advisable.

At the forward end these side-bars are slotted as indicated at 38, to receive bearings 39, 39, in which there is rotating a shaft 40, upon which there is mounted atwo-part sprocket-wheel 41, constituting the driven sprocket, said endless track band being trained over both, driver and driven sprockets.

The shaft 37 passes through bearings 42, 42 formed in the rearwardly located plates 30, 30", (and 31, 31*, respectively) so that the truck frames are pivotally connected to the chassis at their rear ends thereby permitting the forward ends of the same to rise and fall to follow the undulations of the ground over which the tractor is being moved.

Pending from the side-bars 35, 35, there are a series of bearings 43, in which rotate shafts 44. on which are mounted rollers 45, which sustain the endless track band at its lower run, and from said side-bars there V project, upwardly, similar bearings 46, in

which rotate shafts 47, on which are mounted guide rollers 48, that sustain the upper run of the chain C, these and several or all of the guide-rollers 45 being flanged to prevent the chain C from swinging sidewlse.

At the forward ends of the side-bars 35, 35, there are located screw-bolts 49, one end of each being fastened to the corresponding bearing 39; nuts 50 being located on said screw bolts, whichwhen rotated in one direction will draw the bearings 39 in one direction, and when rotated in the opposite direction allow the bearings 39 to move correspondingly. By means of this device I am enabled to take up any slack in the chains (.7 that will occur in course of time by wear of the moving parts.

In order to relieve the machine from the effects of jars and jolts when moving over rough roads, I provide suitable preferably elliptical springs 51, fastened to the forward end of each side-bar, with the chassis in* an approved manner. These elliptical springs are connected at their extremities to one end of upstanding links, 52, Fig. 1, the other ends of said links being pivoted in pairs, to shafts 71, having bearings in brackets or boxes secured to the underside of the longitudinal beams 12, 16, and 19, 13, respectively. By thus flexibly supporting the forward end of the main frame I relieve the machine of most of the jar, jolts and other severe usage to which this class of machines is especially subjected.

Referring to Fig. 1, there is mounted on the bedplate 26 an arouated standard 53, having bearings, 54, for the reception of the engine shaft 27; and between the uprights of this standard there are mounted on engine shaft 27, two, oppositely facing driver friction disks 55. These friction disks engage two friction driven disks 56, mounted on shafts 57, which carry, at their ends gear pinions, 58, that mesh into spurwheels 59, fastened to shafts 60, together with pinions (31, that engage spur-wheels G2 fastened to the shafts 37, to rotate these shafts. and through them. move the endless track band C, as already described.

In order to steer this machine by varying the speed of the endless track bands, I employ mechanism which forms the subject matter of a separate application for Letters Patent filed by me August 20, 1913, Serial No. 785,674, concurrent with this present one, and which includes hand-wheel G3 which, when rotated causes a lateral move ment of the driven friction disks, as fully described in said copending application, while a handlebar 64. and associated mechanism affords means for reversing the movement of the tractor.

I have hereinbefore described but one of the trucks, but have already stated the fact that there are two of these devices. one on each side of the machine: the one shown in Fig. 1 beipg the one located at the right side, and the one shown in Fig. 5 being that of the left side of the tractor.

I shall now call attention to the fact that an imaginary line centers of these two shafts are not in horidrawn horizontally through the center of the shaft 37 forwardly V T zontal alinement, while the centers of the bearing rollers 45 are in horizontal ahnement. It thus follows that at the forward part of the lower run of the endless track belt there are several links between the first bearing roller 45 and-the point where a link of the endless track beltengages the forward sprocket, which are upwardly inclined, thereby forming inclines in the track by which the machine is enabled to readily mount obstruc'tions, etc., in the road, while all the remaining links of the ground run of the endless track between the first bearing roller 45 and a vertical center line through the rear sprocket shaft are normally in horizontal alinement, thereby combining with the ease of mounting obstructions, a maximum tracclaim in this present application, any combination of elements of which this box-like construction forms a part.

Having thus fully described this invention, I claim as new and desire to secure by Letters Patent of the United States 1. In a traction engine, the combination, of a'main frame. a motor mounted on said main frame, and two trucks supporting said main frame. each of said trucks comprising two side plates in parallel spaced relation said side-plates having tubular pivots at one of their extremities and slotted apertures at their opposite extremities, there being pending from the lower edges of said plates a series of bearings. and extending upwardly from the upper edge of said plates further bearings, the lower and the upper bearings being in parallel spaced alinement, brackets secured to the lower flanges of the main frame structure near the rear end thereof. journal bearings at the lower ends of these brackets constructed to engage the tubular pivots at the rear ends of theside-plates, further pendant plates near the front end of the main frame between which the forward ends of the trucksare free to move vertically but prevented from lateral mo 'ement, bearings in the slots at the forward end of said truck side-plates, means at the forward end of said side plates constructed to move and lock said latter bearings in said slots, elliptical springs secured medially to the free ends of saidtruck side-plates, links connected at one of their ends to the extremities of said elliptical springs and at the other ends to said main frame. an endless track-traction belt located between adjacent pairs of truck side-plates, sprocket wheels mounted rotatably at the extremities of said truck sideplates, said endless traction belts being trained over said sprockets, bearing rollers, rotatably mounted in the downwardly extending bearings, rotatably mounted carrying rollers in the upwardly projecting bearings of said truck side plates.

2. In a traction engine, the combination, of. a main frame, a pair of truck-frames located one on each side of and underneath said main frame, said truck frames comprising each a pair of plates in parallel spaced relation, said main frame including L four longitudinal beams in parallel spaced relation, a downwardly extending bracket at each rear end of said beams, a pair of said truck plates being pivotally connected to each adjacent co-acting pair of said rear brackets, a further bracket projecting downwardly from the forward end of reach of said beams, said brackets being constructed to permit of vertical movement of said truck frames but prevent lateral movement thereof, a series of superposed elliptical springs medially secured to the forward ends of said truck frames, links connecting at one of their ends to the extremities of said elliptical springs, and brackets under said beams to which the other ends of said links are connected.

3. In a tractor of the type specified, an endless track-band, said track-band including a series of articulate members, a number of said articulate members having each two, oppositely extending bosses, and a driving sprocket, said driving sprocket comprising a drum constructed to run on said articulate members, said drum having on its two margins radially projecting teeth constructed to engage the said'oppositely-extending bosses. said teeth being outwardly flared to afford approximately sharp edges.

4. In a traction engine of the type described, a truck. said truck comprising two plates in parallel spaced relation, said plates being approximately medially connected by a cross-bar, each plate having at one of its terminals-a tubular trunnion, and at its other terminal a slotted aperture, hearings in said slotted apertures, the center of said bearings being above the center of the tubular trunnions. each of said plates having a multiplicity of downwardly extending bearings. and a series of upwardly projecting bearings, a fixed, non-rotatable, axle constructed to receive the tubular trunnions aforesaid, a shaft constructedto rotate in the hearings in said slotted apertures, said latter shaft carrying two sprocket wheels in spaced relation fixed to said shaft, there being a single sprocket wheel mounted on the fixed axle and constructed to rotate thereon,

carrying Wheels, rotatably mounted in the downwardly extending bearings, carrying wheels, rotatably mounted in the upwardly 5 projecting bearings, and an endless gtrackband trained over said sprocket Wheels.

In testimony that I claim the foregoing as my invention I have hereunto set my hand in the presence of two subscrlblng W1t- MICHAEL J. STARK, A. N. LURIE. 

